At least six robberies occurred between Dec. 18 and Friday. One suspect was described as a short Hispanic male between 20 and 25, the Chicago Sun-Times reported.
Police said one or two people identifying themselves as police officers approached the victims. The primary suspect wore a chain and a silver-colored badge around his neck and carried a police-style radio, flashlight and handgun.
The second suspect served primarily as the driver of a getaway car. The vehicles used in the robberies were described as a red Chevrolet Lumina or Monte Carlo, with gray on the trunk, and a white Chevrolet Suburban.